Contemplating the Mysteries of Life

[bsekf]

Won a Black Gun in a raffle, no great interest, but just had to make sure it went BANG. While shooting it we noticed how hot the ejected cases were. Especially Granddaughter, when one tumbled down the front of her shirt. WHY??? 223's out of a bolt gun aren't burning hot.

I'm sure there is a scientific explanation, but what is it?

Bill

 

[jdh47]

Yes they are you just don't notice it because it takes longer to get them out and you don't usually handle them that much. So freshly ejected cases would be exhilarating to say the least finding one down the shirt. Brass is a good conductor.

Joe

 

[jwink]

With the AR, the spent case is ejected within milliseconds of firing. Thus no time to lose heat. With the bolt gun, the case has a few seconds to lose heat to the chamber. If you shoot a string from the bolt gun, cases will get hotter and hotter as barrel temp goes up.

 

[Geronimo Jim]

The gas tube sends hot gas to chamber to operate the action.

 

[GaryL1959]

Won a Black Gun in a raffle, no great interest, but just had to make sure it went BANG. While shooting it we noticed how hot the ejected cases were. Especially Granddaughter, when one tumbled down the front of her shirt. WHY??? 223's out of a bolt gun aren't burning hot.

I'm sure there is a scientific explanation, but what is it?

Bill

I still have scars from 7.62x51 brass from a M-60...a couple pieces of that down the back of your neck under the collar and wedging under the straps of your web gear will make a dancer out of a young Marine...

 

[GrocMax]

HK91 was a scarifier. Red hot. Plus unpredictable ejection angle and distance. Stand anywhere in the right rear quadrant of the shooter within 20 yards and you play dance dance revolution eventually.

 

[ebb]

what G Jim said

 

[snert]

Once had a female recruit on the line. 40SW went down her shirt. Did not know a shirt vest and bra could fly off that fast. It took quite a while to regain control on the line.

 

[DRNewcomb]

First time I took my young bride shooting. I handed her a H&K P9S .45 ACP loaded with light target rounds. The P9S ejects cases overhead. Well, she limp-wristed the pistol and the first one went down her neck and into her bra. After we got that sorted out and her blouse buttoned all the way up, the 2nd one knocked her in the forehead and dropped between her glasses and her cheek. I've never lived that day down.

WHY??? 223's out of a bolt gun aren't burning hot......I'm sure there is a scientific explanation, but what is it?

Dwell time in the chamber. The brass sits in the chamber where it is cooled by the barrel. Gas guns toss the brass out still glowing.

 

[johnfred1965]

The bolt action chamber acts as a heat sink in just the few seconds it takes to extract the case, leaving it much cooler than a case extracted as soon as the fire is out of it.

G Jim: The gas tube routes hot gas into the bolt carrier to cycle the action. None of that gas comes in contact with the cartridge case.

 

[ebb]

Where does that gas go now that it has opened the bolt? Doesn't the bolt touch the case? The cases that hit the ground from an AR15 are hot many seconds after they hit the ground. yet the 1.5 seconds it that's to manually operate a bolt action cools them down? Doesn't a gas gun have a chamber too?

 

[joshb]

Once had a female recruit on the line. 40SW went down her shirt. Did not know a shirt vest and bra could fly off that fast. It took quite a while to regain control on the line.

Pics? Video would be better.

 

[snert]

First time I took my young bride shooting. I handed her a H&K P9S .45 ACP loaded with light target rounds. The P9S ejects cases overhead. Well, she limp-wristed the pistol and the first one went down her neck and into her bra. After we got that sorted out and her blouse buttoned all the way up, the 2nd one knocked her in the forehead and dropped between her glasses and her cheek. I've never lived that day down.


Dwell time in the chamber. The brass sits in the chamber where it is cooled by the barrel. Gas guns toss the brass out still glowing.

The time a 40SW wedged between an officers eyelid and his shooting glasses was pretty exciting...but I thought my other war story would be more appreciated.

 

[snert]

Pics? Video would be better.

None of the above. It was actually quite scary. She (and we) thought she had been shot. I guess all those westerns that described being shot as a hot searing pain made a home in her head and when there was a bunch of boom boom going on and suddenly her ..ahem...chest got a hot searing pain, well, she sorta jumped to conclusions. It was pretty dang awkward checking for a hole and finding only a heck of a meaty blister. Then it was triage time...do we treat the wound, touch the wound, ice the wound, cover the wound, stand around sayin "aw shucks" and kickin the dirt, tell her to go fix it herself? A time that tried mens souls....

 

[msinc]

Where does that gas go now that it has opened the bolt? Doesn't the bolt touch the case? The cases that hit the ground from an AR15 are hot many seconds after they hit the ground. yet the 1.5 seconds it that's to manually operate a bolt action cools them down? Doesn't a gas gun have a chamber too?

This is a good point and a good question from the OP...the gas that is used to cycle the AR runs down the gas tube, thru the carrier key and into the bolt carrier. It expands and pushes the bolt carrier back unlocking the bolt and continues out the two holes on the side of the carrier. That is not by any means a full accounting of what happens to cycle this rifles action, but it does tell you where the gas goes or what happens to the gas itself. I agree that no gas gets to the chamber...well a little maybe, but it is a very little that leaks thru the firing pin hole in the bolt face. This leak occurs after the bolt is unlocked so I still don't see how any could get into the chamber or be able to heat up the brass case.
If you heat a 223 case with a torch to the same comparable temperature it doesn't cool off that fast either. I agree it is funny how the very first round ejected from an AR is way too hot to touch and remains so for a time, while the very first round immediately ejected from a bolt gun is barely warm?????
The bottom line; you cannot change either one, so the reasons why don't really matter...one will burn the pee out of you, the other you can barely feel. Still a good question though.
Think of the barrel around the chamber as a heat sink, a vessel to hold heat...it has much more mass than the case itself. Now think of heat as a liquid...you could pour a lot of heat into the vessel. Now consider the time it takes to "pour" that heat in to the vessel {chamber area}...whats lacking in the AR is the time to "pour".....

 

[Paul Seaman]

This is a good point and a good question from the OP...the gas that is used to cycle the AR runs down the gas tube, thru the carrier key and into the bolt carrier. It expands and pushes the bolt carrier back unlocking the bolt and continues out the two holes on the side of the carrier. That is not by any means a full accounting of what happens to cycle this rifles action, but it does tell you where the gas goes or what happens to the gas itself. I agree that no gas gets to the chamber...well a little maybe, but it is a very little that leaks thru the firing pin hole in the bolt face. This leak occurs after the bolt is unlocked so I still don't see how any could get into the chamber or be able to heat up the brass case.
If you heat a 223 case with a torch to the same comparable temperature it doesn't cool off that fast either. I agree it is funny how the very first round ejected from an AR is way too hot to touch and remains so for a time, while the very first round immediately ejected from a bolt gun is barely warm?????
The bottom line; you cannot change either one, so the reasons why don't really matter...one will burn the pee out of you, the other you can barely feel. Still a good question though.
Think of the barrel around the chamber as a heat sink, a vessel to hold heat...it has much more mass than the case itself. Now think of heat as a liquid...you could pour a lot of heat into the vessel. Now consider the time it takes to "pour" that heat in to the vessel {chamber area}...whats lacking in the AR is the time to "pour".....

I know the heat you fellas are talking about but,,,, welders get the hot slag dropped down collar and then the dancing starts! I've got a 1/2" scar from a bubble of slag that just popped off a pipe weld when I was on the other side it hit my hood and down my collar it went! Glued to my hide embedded in my skin! Doctors wouldn't remove it had to wait for it to grow out and fall off!

 

[earlcurtis67]

I know the heat you fellas are talking about but,,,, welders get the hot slag dropped down collar and then the dancing starts! I've got a 1/2" scar from a bubble of slag that just popped off a pipe weld when I was on the other side it hit my hood and down my collar it went! Glued to my hide embedded in my skin! Doctors wouldn't remove it had to wait for it to grow out and fall off!

Been there done that!... I've got a nice scar on the top of my foot from slag dropping in a slip-on boot. No more slip-on boots!